This paper describes the development of algorithm for direct data transmission between Raw VLBI Data Buffer (RVDB) and Huge Capacity Data Server (HCDS) operated in Korea-Japan Correlation Center (KJCC). The transmitted data is the VLBI observation data, which is recorded at each radio telescope site, and the data transmitting rate is varying from 1 Gbps, in usual case, upto 8 Gbps. The developed algorithm for data transmission enables the direct data transmission between RVDB and HCDS through 10 Gbps optical network using VLBI Data Interchange Format (VDIF). Proposed method adopts the conventional UDP/IP protocol, but in order to prevent the loss of data during data transmission, the packet error monitoring and data re-transmission functions are newly designed. The VDIF specification and VDIFCP (VDIF Control Protocol) are used for the direct data transmission between RVDB and HCDS. To validate the developed algorithm for data transmission, we conducted the data transmission from RVDB to HCDS, and compared to the transmitted data with the original data bit by bit. We confirmed that the transmitted data is identical to the original data without any loss and it has been recovered well even if there were some packet losses.

ABSTRACT
1. 서론
2. 데이터 전송 규격
    2.1. VDIF 규격 및 구조
    2.2. VDIF 데이터 프레임 구조
    2.3. VDIF 데이터 프레임
3. 데이터 전송 소프트웨어
    3.1. 전송 제어 시퀀스의 개선
    3.2. 개선된 전송 제어 시퀀스를 구현한 소프트웨어
4. 전송실험 및 결과
5. 결론
REFERENCES

• 노덕규(한국천문연구원) | DUK-GYOO ROH (Korea Astronomy and Space Science Institute)
• 오세진(한국천문연구원) | SE-JIN OH (Korea Astronomy and Space Science Institute) Corresponding author
• 염재환(한국천문연구원) | JAE-HWAN YEOM (Korea Astronomy and Space Science Institute)
• 정동규(한국천문연구원) | DONG-KYU JUNG (Korea Astronomy and Space Science Institute)
• 오충식(한국천문연구원) | CHUNG-SIK OH (Korea Astronomy and Space Science Institute)
• 윤영주(한국천문연구원) | YOUNG-JOO YUN (Korea Astronomy and Space Science Institute)
• 김효령(한국천문연구원) | HYO-RYOUNG KIM (Korea Astronomy and Space Science Institute)
• Kensuke Ozeki(Elecs Industry Ltd.)